Solar turf devices systems and methods

ABSTRACT

A device, system, and method for harvesting solar energy from an artificial turf field or other area exposed to sunlight. An array of solar collectors may be placed in a sports stadium or other open field, each solar collector having an artificial turf structure including simulated grass and an open support structure capable of supporting human foot traffic, the artificial turf structure overlying a resilient bed supporting photovoltaic panels. Light falling on the structure at incident angles of 30 degrees from the artificial turf surface normal may be transmitted from the open support structure to the photovoltaic panels, and the panels may convert the transmitted light to electricity. The photovoltaic panels may be oriented to maximize an amount of captured light responsively to latitude. The turf structure support members may be angled responsively to an average direction of the sun at an installation latitude.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional Application No. 61/444,523, filed Feb. 18, 2011, which is incorporated herein by reference in its entirety.

BACKGROUND

Artificial turf is used in athletic fields such as football pitches and baseball fields as well as golf courses. It is also used for landscaping. Artificial turf provides benefits including durability, consistent appearance, environmental advantages such as avoidance of the need for polluting fertilizers, polluting maintenance equipment such as mowers, and rapacious consumption of water. The solar energy that normally bathes artificial and natural turf areas is a wasted resource. It would be of significant value to exploit areas covered by turf as a low impact solar resource, as proposed by University of Florida Research Foundation which has filed for a PCT application published as WO/2009/070706. This application describes an artificial turf structure of solar blades each defining a photovoltaic component. The system proposes a structure for collectors that mimic grass and has various specific requirements and associated potential advantages and disadvantages. There remains a need for new approaches that can exploit the energy resource represented by artificial turf and efficiently harvest the solar electricity.

SUMMARY

A solar collector in accordance with one or more exemplary embodiments of the present invention may include an artificial turf structure including simulated grass and an open support structure capable of supporting human foot traffic, the artificial turf structure overlying a resilient bed supporting photovoltaic panels, the open support structure transmitting to the photovoltaic panels at least 30% of light falling thereon at incident angles of 30 degrees from the artificial turf surface normal. The support structure may be a truss layer of polymer or polyurethane, and the simulated grass may include tufts supported by stems depending from a level below a top surface of the support structure. Additionally, the tufts may be made of transparent material. The photovoltaic panels may be spaced apart to permit drainage through a resilient bed, and the resilient bed may be porous. The photovoltaic panels may include cells embedded or encapsulated in polymer to form a unitary ruggedized unit. A system in accordance with one or more exemplary embodiments of the present invention may include an array of solar collectors in accordance with one or more exemplary embodiments of the present invention, arranged in a sports stadium or other open field.

A solar collector in accordance with one or more exemplary embodiments of the present invention may include a support structure supporting an artificial turf structure in spaced relation to a ground surface, and an array of photovoltaic panels disposed below the turf structure, the turf structure being substantially open to permit an amount of light to pass through the turf structure to the array of photovoltaic panels. The amount of light permitted to pass through may be at least 30%. The turf structure may include an artificial turf with simulated grass and an open support structure capable of supporting human foot traffic. The turf support structure may be a truss layer of polymer or polyurethane, or both. The simulated grass may include tufts supported on stems that extend from a level below a top surface of the support structure. The simulated grass may include tufts of transparent material supported on stems that extend from a level below a top surface of the support structure. The photovoltaic panels may be spaced apart to permit drainage through a resilient bed, and the resilient bed is porous. The photovoltaic panels may include cells embedded or encapsulated in polymer to form a unitary ruggedized unit. The simulated grass may include tufts attached to a web layer that is separate from the support structure, for allowing the web layer and tufts to be replaced separately from the support structure. The collector may include a sheet, screen, mesh, or veil fixed above the photovoltaic panels and below the support structure, and the sheet, screen, mesh, or veil is may optionally be tinted, translucent, and/or perforated.

A system in accordance with one or more exemplary embodiments of the present invention may include an array of solar collectors in accordance with one or more exemplary embodiments of the present invention, arranged in a sports stadium or other open field.

A component for a functional ground system in accordance with one or more exemplary embodiments of the present invention may include an artificial turf structure including simulated grass and an open support structure capable of supporting human foot traffic, the artificial turf structure overlying a resilient bed supporting light emitting panels, the open support structure permitting at least 30% of light from the light emitting panels to pass through the artificial turf structure. The support structure may be a truss layer of polymer or polyurethane, or both. The simulated grass may include tufts supported on stems that extend from a level below a top surface of the support structure. The simulated grass may include tufts of transparent material supported on stems that extend from a level below a top surface of the support structure. The light emitting panels may be spaced apart to permit drainage through the resilient bed, and the resilient bed may be porous. The light emitting panels may include cells embedded or encapsulated in polymer to form a unitary ruggedized unit.

A device in accordance with one or more exemplary embodiments of the present invention that include a photovoltaic panel, may include the photovoltaic panel such that the photovoltaic panel is oriented to maximize an amount of captured light responsively to a latitude. The turf structure support members may be angled responsively to an average direction of the sun at an installation latitude.

A method for efficiently harvesting solar energy in accordance with one or more exemplary embodiments of the present invention may include placing an array of solar collectors in a sports stadium or other open field, each solar collector including an artificial turf structure including simulated grass and an open support structure capable of supporting human foot traffic, the artificial turf structure overlying a resilient bed supporting photovoltaic panels; transmitting from the open support structure to the photovoltaic panels at least 30% of light falling on the structure at incident angles of 30 degrees from the artificial turf surface normal; and converting the light transmitted to the photovoltaic panels to electricity.

BRIEF DESCRIPTION OF THE DRAWINGS

The utility, objects, features and advantages of the disclosed subject matter will be readily appreciated and understood from consideration of the following detailed description of the embodiments of this disclosed subject matter, when taken with the accompanying drawings, in which same numbered elements are identical.

FIG. 1 shows a cross-section of a portion of an artificial turf structure according to an embodiment of the disclosed subject matter and illustrating features that may be combined with those of other embodiments.

FIG. 2 shows a cross-section of a portion of an artificial turf structure according to another embodiment of the disclosed subject matter and illustrating features that may be combined with those of other embodiments.

FIG. 3 shows a cross-section of a portion of an artificial turf structure according to yet another embodiment of the disclosed subject matter and illustrating features that may be combined with those of other embodiments.

FIG. 4 shows a porous bed with wells for functional panels according to an embodiment of the disclosed subject matter.

FIG. 5 shows functional panels arranged in the wells of the porous bed of FIG. 4 according to an embodiment of the disclosed subject matter.

FIG. 6 shows a completed artificial turf structure according to an embodiment of the disclosed subject matter.

FIG. 7 shows a top of view of artificial turf modules with irregular boundaries according to an embodiment of the disclosed subject matter.

FIG. 8 shows a cross-section of a portion of an artificial turf structure according to yet another embodiment of the disclosed subject matter and illustrating features that may be combined with those of other embodiments.

FIG. 9 shows another embodiment of an artificial turf structure which may be used with any of the embodiments.

FIGS. 10 and 11 show a portion of an artificial turf structure according to an embodiment of the disclosed subject matter and illustrating features that may be combined with those of other embodiments, with FIG. 10 showing a cross section and FIG. 11 showing a plan view of a supporting portion of the structure of FIG. 10.

DETAILED DESCRIPTION

Referring to FIG. 1, a solar collecting artificial turf structure 100 has a porous bed 102 of resilient material that supports encapsulated functional panels 104 arranged in an array. Overlying the panels 104 and bed 102 is a simulated turf mat 101. The turf mat 101 includes an open lattice mat 108 with attached blade tufts 106 which simulate grass. The blade tufts 106 may be welded to, for example, or otherwise attached to the lattice mat 108. The lattice mat can be configured to provide support for foot traffic and resist shear and wear due to downward pressure from foot traffic. By arranging the blade tufts 106 within the open lattice mat 108, the lattice mat can protect the blade tufts 106 to a large degree and ensure the blade tufts remain erect to simulate natural or live grass. The open structure of the lattice mat 108 allows a good proportion of incident light to pass through to the functional panels 104 positioned below the lattice mat.

The functional panels 104 may include solar collectors (e.g. photovoltaic cells and panels) or light-emitting devices such as lamps, photodiodes or light-emitting diode (LED) arrays. They may include multiple types of functional panels 104 among other types including light and/or pressure sensors, voltage regulators, control panels, voltage boosters, inverters, rectifiers, transformers, voltage and/or current regulators or energy storage devices such as batteries, ultracapacitors, etc. The functional panels 104 may also include communications devices such as wireless relay stations or wireless control devices. The functional panels are preferably ruggedized by enclosing in polymer boxes or encapsulating in a resin block.

In an exemplary embodiment, the functional panels 104 are arranged in an array covering a recreational field or landscape such as a football field, golf course, or baseball field. In this embodiment, the functional panels 104 may be mostly photovoltaic converters that are interconnected by a suitable mechanism. Other functional panels 104 may provide electrical service functions such as voltage regulation, safety switching, insolation measurement, and other functions. The turf mat 101 protects the functional panels 104 by distributing impact and/or pressure over a wide area of the functional panels. The turf mat 101 is configured into a truss-like structure of resilient material that bends under impact and deforms under shear and pressure loading followed by recovery. The functional panels 104 are further protected by being fitted into the porous bed 102.

The blade tufts 106 and the open lattice mat 108 can be formed of a polymer. The blade tufts 106 are preferably formed of a material that allows transmittance of as much solar energy as possible. For example, they may be transparent with a tint to give the appearance of grass. The blade tufts and open lattice mat may also be coated with UV-screening material and be fitted with optimally sited optical elements that can modify the turf appearance or scatter/direct light onto the photovoltaic elements beneath. In embodiments in which at least some of the functional panels 104 include photovoltaic converters, the tinting may be selected to pass light of a range of wavelengths that best overlaps the range of wavelengths over which the photovoltaic converter is most efficient. The blade tufts 106 may also be configured with a minimum number/density of blades required to provide the desired appearance. Preferably, the open lattice 108 is of a material that matches the blade tufts 106 in appearance. The open lattice and blade tufts may also have properties that provide yield and springiness of the turf.

The porous bed 102 may be of any suitable material such as, for example, material used in modern playgrounds. For example, elastomers such as sintered shredded rubber waste (e.g. tires), open cell foam, or an open truss-structure may be used. Referring for the moment to FIG. 4, the porous bed 102 may be laid down and simultaneously molded with recesses 180 impressed therein. Busses 172 or other kinds of wiring such as signal wiring or cabling, appropriately insulated, may be laid down in the porous bed 102. Anchor points 184 may be distributed as required for securing the lattice mat 108. Then, as illustrated in FIG. 5, the functional panels 104 are then laid down into the recesses 180 and as necessary, interconnected or connected to a buss 172. In order to avoid a bluish appearance of the turf from such an open structure (since for example, silicon cells can have a blue shiny appearance), panels may be encapsulated or covered with materials having a greenish tint. As shown in FIG. 6, the lattice mat 108 may then be laid over the functional panels and anchored to the anchor points 184.

The open lattice 108 may include spokes 110 of a strong and resilient material with low creep. For example, polyurethane, polyethylene, polypropylene, rubber and the like. The structure of the spokes may be designed to provide resistance to shear and a yield that mimics natural turf. The truss-like structure of the open lattice 108 may be configured to permit as much light to pass through it as possible, with consideration of a wide range of apparent angles of the sun during the course of a day. For example, the spokes 110 may be near vertical and have a low aspect ratio in cross-section. Alternatively, the spokes may be flat but their primary surface may be aligned in the North-South direction to ensure that the sunlight is minimally blocked during midday.

Referring now to FIG. 2, a solar collecting artificial turf structure 120 also has a porous bed 102 of resilient material that supports encapsulated functional panels 104 as in the embodiment of FIG. 1. The present embodiment shows features that may be combined with any of the features of the other embodiments. For example, on top of, and overlying the panels 104 and bed 102, a simulated turf mat 121 has an open lattice mat 128 with a non-flat surface 116. The surface 116 may improve the purchase of athletes using the artificial turf structure 120, thus increasing the ability to apply or exert power against the turf during athletic activity. The undulations in the surface 116 may be regular or irregular and may include dense (high frequency) components (not shown) to ensure that the top surface has desired properties in terms of its appearance and mechanical performance, in addition to, or instead of gradual undulations.

The blade tufts 112 may be welded to, for example, or otherwise attached to the open lattice mat 128. As above, by arranging the blade tufts 112 within the open lattice mat 128, the latter can protect the blade tufts 112 to a large degree and ensure that the latter remain erect to simulate real or natural grass. Another feature shown in FIG. 2 is that the blade tufts 112 are attached to a web 114 which is separate from the open lattice mat 128. This may allow the web 114 and blade tufts 112 to be replaced separately from the open lattice mat 128. The web 114 may include a thin tinted or translucent sheet, screen, mesh or veil with periodically located drain holes if necessary, that allows for water drainage and avoids dust or dirt collecting on the panels below. The web could be maintained and cleaned for relatively minimal cost.

Referring now to FIG. 3, a solar collecting artificial turf structure 140 also has a porous bed 102 of resilient material that supports encapsulated functional panels 104 as in the embodiments of FIGS. 1 and 2. The present embodiment shows features that may be combined with any of the features of the other embodiments. Blade tufts 134 are attached onto stems 132. This configuration can provide a greater open area below the top 143 and surface 116, while providing a similar appearance as viewed from the top 143 of the open lattice mat 128.

The artificial turf structures shown above may be made from modules that are tiled or fit together to form a macroturf structure. In an exemplary embodiment, the modules may be configured with irregular boundaries as indicated at 100 in FIG. 7 to give an installed system a more natural appearance. Alternatively, the modules may be configured with varying geometric boundaries (not shown) to give an installed system a specific patterned or logo-based appearance.

Additional layers may be provided in an installed system according to suitable methods and structures. For example, a gravel, limestone or supplementary elastomeric bed may be installed to support the porous bed 102. Drainage conduits may be provided within or beneath the gravel bed. Also, power and communications wiring may be provided below the porous bed 102. Electrical components may be provided outside the array of functional panels 104 such as terminals, junction boxes, controllers, inverters, voltage boosters, and monitoring systems.

Referring now to FIG. 8, another feature that may be combined with any of the foregoing embodiments, or replace features thereof, is a blade tuft support 192 that stems from a level above the base of the open lattice mat 196. The support 192 may support blade tufts (e.g., 194) as in any of the foregoing embodiments. The blade tufts can be shortened as needed to ensure a proper fit within the artificial turf structure 190.

In other exemplary embodiments (not shown), blade tufts may stem from the top of an open lattice mat. For example, as shown in FIG. 9, tufts 234 may be integral or attached to an open lattice 238. In this embodiment, the tufts maybe form a mat or tile that is attached to the open lattice.

Referring to FIGS. 10 and 11, the artificial turf support 220 has vertical 222 and horizontal 224 supports forming square sections (aligned horizontally and extending into the plane of the page so that they intersect as a line with the plane of the page of FIG. 1 and as viewed from above in FIG. 11) closed by a mesh or screen 226. The mesh or screen 226 supports an open lattice mat 202. The lattice mat 202 has truss elements 218 that are shaped and angled to minimize blocking of light when oriented appropriately. A variety of structures may be devised to satisfy the condition of low light blocking with sun angle, and various tradeoffs may be employed in optimizing their shape and orientation for different climates, latitudes, and desired functional criteria to be optimized.

As in previous embodiments, blade tufts 204 may be provided as a separate mat or may be made integral to the open lattice mat 202. A porous supporting bed 212 made, for example, of gravel may be provided. Conventional methods and structures may be employed as are suitable to provide for drainage and solid support. Functional panels 208, for example photovoltaic panels, can be supported and oriented by a panel support 210. The panel support 210 may include a porous bed as discussed in other embodiments. Since the support 220 is able to handle the load applied to the artificial turf structure 200, the panel support 210 may also be a lightweight molded support such as, for example, a vacuum molded tray. The functional panel 208 may be covered by a clear cover 206. Gutters 216 may also be provided and drain holes as required may be provided in the panel support 210. The support 220 may have triangulation provided by additional structural members according to suitable devices for forming support structures.

In another embodiment (not shown) the open lattice mat may not have horizontal stringers (such as that indicated at 198) and may include only upwardly directed pillars. Spokes may be arranged in any suitable fashion to create a desired support and performance. In further embodiments, the open lattice mats may be transparent or translucent as are the blade tufts. In yet other embodiments, the blade tufts may be sufficiently sparse that they may be opaque (e.g. being formed of an opaque material or coated with an opaque substance).

Bladed tufts may be attached by welding, weaving, or other suitable securement means. The tufts may have round cross-sections or other cross-section shapes, and may have a cross-section that differs from that of natural turf blades. The components may be formed as modular units, as tiles, as rolls, or as large mats as desired. Where components are in abutting arrangement, they may be interconnected by any suitable mechanism such as, for example, by clips, studs, a continuous polymer seam such as on a baseball, or screw, rivet, nut and bolt, or other fasteners with appropriate interlinking bosses stemming from the components, such as the open lattice mat, the blade tuft mat, the support structure (support 220 in FIG. 10), etc.

In exemplary embodiments, the functional panels may be photovoltaic panels or modules between 10 and 30 cm square or alternatively, rectangular with edges in the range of 10 to 30 cm. Such sizes are illustrative only and not intended to be limiting of the scope of the claimed invention. In exemplary embodiments, the functional panels include individual cells providing typically 0.5V and 2 W in full unshaded sunlight or up to 5 W at 12V in larger sized panels such as 30 cm×30 cm. Preferably, the aggregate efficiency of the artificial turf structure is at least 5% at peak solar conditions. This may be achieved using photovoltaic cells having 15% efficiency with the artificial turf above the functional panels permitting passage of about a third of the solar light in cases where the incoming light forms an angle of 30 degrees from the vertical or the top surface normal (e.g., incident angle for horizontal surface). Alternatively, lower cost cells/panels with lower efficiencies may be used.

Potential applications for the artificial turf embodiments include golf courses, football stadiums, parks, highway mediums, open-air theaters including stage and seating/walking areas, sport fields, parking lots, sidewalks, driveways, residential landscaping and other applications. Functional panels that include light-emitting devices may be used to generate digital displays and light shows, for example at sports stadiums.

It will be apparent to those skilled in the art that various changes may be made in the above-described embodiments of the present invention. However, the scope of the present invention should be determined by the following claims. 

1. A solar collector, comprising an artificial turf structure including simulated grass and an open support structure capable of supporting human foot traffic; the artificial turf structure overlying a resilient bed supporting photovoltaic panels; the open support structure transmitting to the photovoltaic panels at least 30% of light falling thereon at incident angles of 30 degrees from the artificial turf surface normal.
 2. The collector of claim 1, wherein the support structure is a truss layer of polymer.
 3. The collector of claim 1, wherein the support structure is a truss layer of polyurethane.
 4. The collector of claim 1, wherein the simulated grass includes tufts supported by stems depending from a level below a top surface of the support structure.
 5. The collector of claim 1, wherein the support structure is a truss layer of polymer and the simulated grass includes tufts supported by stems depending from a level below a top surface of the support structure.
 6. The collector of claim 1, wherein the support structure is a truss layer of polymer and the simulated grass includes tufts of transparent material supported by stems depending from a level below a top surface of the support structure.
 7. The collector of claim 1, wherein the support structure is a truss layer of polymer and the simulated grass includes tufts of transparent material.
 8. The collector of claim 1, wherein the support structure is a truss layer of polyurethane and wherein the support structure is a truss layer of polymer and the simulated grass includes tufts of transparent material supported by stems depending from a level below a top surface of the support structure.
 9. The collector of claim 1, wherein the simulated grass includes tufts supported by stems depending from a level below a top surface of the support structure and the support structure is a truss structure of polymer and the simulated grass includes tufts of transparent material.
 10. The collector of claim 1, wherein the photovoltaic panels are spaced apart to permit drainage through the resilient bed.
 11. The collector of claim 1, wherein the photovoltaic panels are spaced apart to permit drainage through the resilient bed and the resilient bed is porous.
 12. The collector of claim 1, wherein the photovoltaic panels include cells embedded or encapsulated in polymer to form a unitary ruggedized unit.
 13. A system including the collectors of one of claims 1-12, the system including an array of the collectors arranged in a sports stadium.
 14. A solar collector, comprising: a support structure supporting an artificial turf structure in spaced relation to a ground surface; and an array of photovoltaic panels disposed below the turf structure; the turf structure being substantially open to permit an amount of light to pass through the turf structure to the array of photovoltaic panels.
 15. The collector of claim 14, wherein the amount of light is at least 30%.
 16. The collector of claim 14, wherein the turf structure includes an artificial turf including simulated grass and an open support structure capable of supporting human foot traffic.
 17. The collector of claim 16, wherein the turf support structure is a truss layer of polymer.
 18. The collector of claim 16, wherein the support structure is a truss layer of polyurethane.
 19. The collector of claim 16, wherein the simulated grass includes tufts supported on stems that extend from a level below a top surface of the support structure.
 20. The collector of claim 16, wherein the support structure is a truss layer of polymer and the simulated grass includes tufts supported on stems that extend from a level below a top surface of the support structure. 